Misfit dislocations:An atomistic and elastic continuum approach

This paper presents the results of an atomistic model in which the misfit and the bond strength between a metal and a substrate can be controlled. The model is applied to a simple case, i.e. an interface with misfit in one direction. Calculated energies are presented and the corresponding atomic structures for various misfits and interaction parameters are discussed. It turned out that the structure of the misfit dislocations depends both on misfit and bond strength. A trend from delocalized structures to localized structures that resemble bulk-like dislocations can be seen for decreasing misfit at constant interaction parameter, and increasing interaction parameter at constant misfit. This atomistic approach is compared with a description based on linear elasticity theory of interface dislocations. Although a fair correlation exists between these two different concepts, it is shown that the elastic continuum approach cannot account for the possible configurations at an interface, because it does not contain any information on the effects different bond strengths may have on the interface structure. (C) 1997 Acta Metallurgica Inc.